Place the king prawns, garlic, Pecorino Romano, sea salt, white pepper, onion powder, garlic powder, mustard seeds, and olive oil in a plastic closeable bag.
Seal the bag and shake to coat the prawns thoroughly.
Preheat the Air Fryer to 390°F (200°C).
Lightly grease the Air Fryer basket and transfer the coated king prawns into it.
Cook for 6 minutes, shaking the basket halfway through.
Cook in batches if necessary.
While the prawns are cooking, melt butter in a small saucepan over medium heat.
Add lemon juice, Worcestershire sauce, and black pepper to the melted butter.
Reduce the heat to low and whisk the sauce for 2 to 3 minutes until thoroughly heated.
Spoon the lemon butter sauce over the warm king prawns before serving.
Serve immediately and enjoy this elegant dish.
Notes / Tips / Wine Advice:
Wine AdvicePair with a crisp Sauvignon Blanc or a dry Riesling to enhance the citrusy flavors of the sauce.